Centimeter- and millimeter-wave communication deals with difficult channels characterized by high path loss, multipath propagation, and blocking. Massive MIMO beamforming (BF) not only compensates for the path loss but also mitigates multipath in the sense that the beam-formed channel, that may be represented by the cascade of transmitter beamformer, physical channel and receiver beamformer “reduces” to an equivalent sparse channel, typically comprising the LOS path 101 and a few reflected NLOS paths 102, 103 or clusters as illustrated in FIGS. 1 and 2, where each cluster is characterized by a cluster power, delay/Doppler shift (possibly large), and a small delay/Doppler spread.
It may thus be desirable to provide a technique for improving communications in such environments as described above.